The world has experienced changes in climate within the past few decades. This has largely impacted on the agricultural industry. The gradual change in rainfall patterns and seasonal changes alter the type of quality of feed available to livestock. This challenge, coupled with the rapid increase in the demand for livestock products has resulted in sky rocketing prices of cow feed. Since the crop production and processing industry produces a lot of waste, studies have been conducted to find out whether cows can feed on rhubarb and other excess vegetables produced primarily for human consumption. Results indicate that cows can eat rhubarb, however some parts of the plant are toxic and can negatively affect health and production.

Rhubarb Supplements for Ruminants

Rhubarb is said to be highly nutritious and so can be provided to livestock as a means of supplementing nutrients lacking in their daily dietary plans. Rhubarb is highly famed for its have medicinal effects. It consists of carbohydrates, fibre, some protein, vitamins and minerals such as calcium, magnesium, potassium and folate. Cows can feed on rhubarb to absorb these nutrients. An important point to note is that rhubarb is lacking in some essential nutrients and minerals. It contains a significantly low amount of sodium and vitamin B-6 among others. Furthermore, rhubarb contains phenolic acid which is known for its superior abilities of preventing the occurrence of oxidation. As already pointed out, certain parts of the plant are poisonous while other parts are not. Research indicates that cows can feed on rhubarb leaf stalks but cannot eat the leaves as they are very poisonous. Rhubarb contains oxalate acid which is highly concentrated in the leaves. For this reason, although cows can eat rhubarb stalks, under no circumstances should they be given leaves. Farmers should also be aware that rhubarb stalks also contain this toxic compound though in limited amounts. Therefore when using rhubarb as feed supplements, care should be taken to include it in small amounts. This is because toxicity generally increases with specific rations. Some farmers dismiss usage of rhubarb as ruminant food altogether due to its toxicity. However, to ranchers knowledgeable about the vegetable and appropriate rations, rhubarb proves to be quite beneficial to production.

Rhubarb Leaves Poisoning

Rhubarb leaves are primarily meant for human dietary plans and this should be maintained. A variety of studies conducted on feed alternatives for cows indicate that cows should not eat rhubarb leaves. Experts concur, stating that rhubarb leaves can potentially have detrimental effects on health and production. In severe cases, the entire agricultural venture can be at risk. Despite the fact that cows can eat rhubarb, it is considered as a complicated feed alternative as it can only be used in special rations and some parts such as leaves are toxic. This calls for the need for farmers to acquire adequate knowledge on the rations, toxic parts and effects of excess feed on health and production. Cows can tolerate small amounts of rhubarb leaves. In fact, cows have been known to feed on rhubarb leaves during drought when forage cannot sustain their dietary plans without any negative effects. However, as rations consumed increase, so does the toxicity of the fruit. Cows that consume excess rhubarb leaves suffer from health related issues that can potentially lower production levels, hence the profitability of the agricultural venture. Signs of rhubarb leaves poisoning include diarrhoea, depression, trembling, staggering, excessive salivation and frequent urination. Keep in mind that poisoning does not occur with limited amount but excess feed can even lead to kidney failure and death.

What plants are poisonous to cows?

Although cows can feed on rhubarb stalks, they cannot eat the leaves as they are toxic. The next consideration therefore is whether or not cows can feed on all plant matter or some are toxic. Studies reveal that cows can eat rhubarb and most plant material. In fact, some plants are said to be toxic to other domestic animals and even sheep yet cows can have some form of tolerance to them. This does not mean that cows can eat all plant matter, some plants are highly toxic to such an extent they may have detrimental effects on cattle. Plants such as lupines, death camas, nightshades, poison hemlock, water hemlock and larkspurs are highly toxic to cows. To add on, cows should not feed on brassica plants including spinach and sukuma. Avocados contain persin and so are also poisonous to cows. The same applies to hairy vetch which is known to cause kidney failure. The following are some poisonous plants:

Name Poisonous Part Type of Poison
Pigweed Leaves Nitrate
Brassica plants including cabbage, turnips, broccoli, mustard, rape Roots and Seeds Glucosinolates, anaemia factor
Lupine Seeds Lupinine, anagyrine, sparteine and


Oleander Leaves and Stems Nerioside, oleandroside, seaponins, cardiac glycosides
White Sweet Clover and Yellow Sweet Clover Stems Dicooumarol
Wild, Black, Bitter, Choke and Pin cherries Leaves and Seeds Amygdalin and prunasin
Oak Acorns and Young leaves Gallotannins, quercitrin and quercitin
Nightshade Family Leaves and immature


Solanine and soladulcidine


What Should You Not Feed Cows?

Although the dietary system of ruminants is primarily designed to digest plants, cows cannot feed on rhubarb leaves and many other plants. Some plants contain toxic compounds that weaken the immune system resulting in severe illnesses. As a result, production is significantly lowered and so is the success of the farming venture. It is therefore of the utmost importance for farmers to have detailed knowledge about the nutritional value of the plant as well as its mineral compounds. Cows cannot eat plants such as lupines, nightshades, larkspurs, death camas, water hemlock and poisonous hemlock. Similar to rhubarb, there are some human diets with toxic compounds at a capacity that is beyond the tolerance of cows. Food that may poison cattle include cabbage as well as most plants belonging to the brassica family. Beans, onions should also not be fed to cows. Some of these foods are palatable to cows and so it is the farmers’ responsibility to make sure that the grazing land does not contain toxic plants.